Telephone line clearing relay



p 22, 1954 F. c. BALDIK ETAL TELEPHONE LINE CLEARING RELAY 2Sheets-Sheet 1 Filed Feb. 21, 1961 Frank C. Bald/7r Daniel .SfraszewskiINVENTORS P 22, 1954 F. c. BALDlK ETAL 3,150,237

TELEPHONE LINE CLEARING RELAY Filed Feb. 21, 1961 2 Shets-Sheet 2 Fig.424 54 Frank 0. ea/wk 56 Daniel .Sfraszews/r/ I IN VEN TORS 28 Maw 8mUnited States Patent Office hrs-l 3,150,237 TELElHGNE ENE LEARH IG FrankG. Ealdilr, 1312 4th Ave. E, and Daniel Eltraszewski, Rte. 1, .iverRoad, both of Kalispell, Mont. Filed Feb. 21, 1953, See. No. 99,817 9Claims. (1. ri -81) This invention relates to a line clearing system foruse with telephone lines to which more than one telephone is operativelyconnected but enabling a single telephone to be operative at one time.

Under present telephone party line systems to which the present deviceapplies, a problem is created when one telephone on the line becomesinoperative because of inadvertent uncradling of the telephone receiverfrom the cradle switch. When such a situation occurs, it is oftenrequired that all of the party line users of the telephone line hecanvassed in order to isolate the faulty telephone in order to clear theline for the other users. The present invention therefore solves theaforementioned problem by providing a central switchboard signal thatmay be received by the uncradled telephone to not only provide a signalfor the telephone subscriber that his telephone may be inadvertentlyuncradled but will also clear the line for the other telephonesubscribers.

It is therefore a primary object of this invention to provide a relaydevice by means of which a centrally dispatched signal may restoreoperation to the telephone line to which a plurality of party lines areconnected by opening the line to the telephone instrument which has beeninadvertently uncradled.

Another object of this invention is to provide a line clearing relaydevice which not only signals the subscriber but also disconnects thefaulty telephone from the line which may be readily restored to normaloperation by replacement of the hand piece on the cradle switch.

An additional object of this invention is to provide a telephone lineclearing relay device which includes a selectively actuated reset buttonthrough which the line clearin g device may be reset for reception of aline clearing signal and also to render the telephone operative fornormal operation. The line clearing relay device of the presentinvention therefore includes a line clearing circuit which is connectedbetween the telephone book switch and the telephoneline to the telephoneinstrument, which line clearing circuit is normally closed so thatclosing of the cradle switch for transmission of messages through thetelephone line will not be normally disturbed. However, when the cradleswitch of a particular telephone instrument is inadvertently uncradled,to thereby close the telephone circuit through the line clearingcircuit, a centrally dispatched line clearing signal current ofsufficient magnitude energizes a relay switch mechanism to open the lineclearing circuit in order to restore operation to the telephone line forthe other telephone subscribers. The relay switch mechanism isordinarily held in inoperative position in which the line clearingcircuit is held closed by a latch mechanism. When the relay switchmechanism is energized by the signal, however, to open the line clearingcircuit, the latch is also released and is then effective to hold therelay switch mechanism in its circuit opening position after cessationof the line clearing signal. Thereafter, normal operation of thetelephone may be restored by relatching of the latch mechanism eithermanually or by replacing the telephone hand piece on the cradle switchwhereupon the relay switch mechanism will be restored to its inoperativeposition and relatched therein by the latch mechanism.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FEGURE 1 is a partial perspective view of the installation of the lineclearing relay device within a telephone instrument.

FTGURE 2 is a side elevational view of the line clearing relay deviceitself.

FIGURE 3 is a front view of the device illustrated in FIGURE 2.

FlGURE 4 is a sectional view taken through a plane indicated by sectionline i -4 in FlGURE 2.

FIGURE 5 is a side elevational view similar to that of FIGURE 2 butillustrating the relay device in an operative line clearing position.

FIGURE 6 is a sectional view taken through a plane indicated by sectionline 66 in FIGURE 5.

FlGURE 7 is a partial perspective View of the latch eehanism in aninoperative latched position corresponding to that of FIGURE 2.

FEGURE 8 is a partial perspective view of the latch mechanism in anoperative position corresponding to that or" FIGURE 5.

FIGURE 9 is a schematic circuit diagram of an operatively installed lineclearing relay device.

Referring now to the drawings in detail, it will be observed from FIGURE1 that the line clearing control deice generally referred to byreference numeral lit is mounted .on the base 12 of a telephone subsetfor operative contact with the telephone book switch lever and handpiececradle 1d, of the telephone subset. When the telephone hand piece iscradled, the telephone switch lever 16 engages and depresses the pushbutton actuator 13 of the control device it for conditioning the relaydevice it for reception .of a line clearing signal and to condition thetelephone receiving c rcuit for normal operation. The line clearingrelay device it is accordingly mounted in operative relation to thecradle switch lever 16 by a mounting bracket Referring now to FIGURES 2,3 and 4, it will be observed that the relay device ill itself is mountedon a control frame 22 which mounts a control coil 24 within which therelay core 26 is mounted and projects below the bottom of the coil inoperative relation to an armature portion 2-3. A pair of operating arms39 and 32 are pivotally mounted by the frame and interconnected at thelower ends thereof by the armature portion 28. The operating arms 3% and32 respectively have connected thereto at the upper ends, inwardlyprojecting tab formations $4 and 36 which cooperate with a latchformation 38 on the lower end of a latch slide member 49 to which thepush button 13 is connected forming part of a reset latch m chanism 42.The slide member 49 is accordingly slidably mounted by the relay frame22 and is ur ed upwardly from the position illustrated in FEGURES 2 and3 by a spring element 44 which reacts between the shoulder on a tubularguide member 45 connected to the top of the relay frame 22 Within whichthe slide member ll is slidingly received and the bottom of the pushbutton 18. The projecting end portion 36 of the operating arm member 32is in contact with an operating leaf spring member 48 which may bedisplaced from its illustrated position in FIGURE 2 for displacingtherewith the switch operating rod memer Ell by the insulated push rodelement 52. The switch rod 5d as illustrated in FIGURE 2 is inelectrical contact with the fixed switch rod member 54 mounted in aswitch block 56. Also mounted within the switch block 56 asschematically illustrated in FIGURE 9 is a time delaying capacitor 61.electrically connected across and any circuit connected thereto.

a a a a the. terminals 53'and 6d of theswitch rod members 50 and 54. a

Referring now to FIGURES 5 and 6, it will be observed that theelectro-magnetic'relay coil 24 has been energized so as to attractthereto the armature portion 7 23 causing pivotal displacement of theoperating arms 136 and 32 to a circuit opening position causing the projecting tab portionSd thereof to displace the operating spring member 48and switch rod 50 so as to open the contacts between the switch rod 50and switch rod member 54- to therebyopen the circuit to which theterminals 58 and 60 of the switch boX 56 are connected. It will also beobserved that when the latch mechanism 42 has been released, the spring44 thereof will upwardly bias the push button 18- to a releasedposition. The'relay mechanism is accordingly in an operative positionwhen the latch mechanism 42 is in its unlatched position.

, Referring now to FIGURES 7 and 8, it will be observed that when thelatch mechanism 42is in its latched condition, the'bar formation 38 atthe lower end of the latch rod slide member 40 is engaged beneath theprojecting tab 34 of the operating arm 31) which is'then in itsinoperative position as described with respect to FIG- URE' Z'to therebyhold the latch rod member 4% retracted against the bias of the springelement 44 urging the latch rod member 4%) upwardly. When the relay coil.24 is energized 'to pivotally displace the operating arms 39 and 32 toa position relative to the latch mechanism as illustrated in FIGURE 8,the. latch portion 33 and latch rod 4% will be biased upwardly to aposition as illustrated in FlGURE 8 in which case the latch portion 36is disposed rearwardly of the projecting tab 34 I whilethe tabi36 hasengaged the operating spring member 48 and the switch member '59 to openthe switch When the relay :coil 24 is deenergized, return of theoperating arms fill and 32 to the de energized position will beprevented by the latch formation 33 on the latch mechanism which is thendisposed behind the tab 34 as illustrated in FIG- URE 8. Accordinglygtheswitch mechanism is held in its operative or open position, as describedwith respect to FIGURE 5. In order to reset and relatch the operatingarms in their inoperative position, it will only be necessary to depressthe button 13 connected to the latch rod member 44 in which case thelatch formation 38 will, move downwardly from the position illustratedin FIGURES to permit the operating arms to return to their originalposition and be latched therein when the reset button 18 is releasedpermitting the spring 44 to again upwardly bias the latch formation33against the underside of the projecting tabs 34.

From the foregoing description of the relay device construction,operation of the line clearing relay system of the present inventionwill become apparent. Referring therefore to FlGURE 9 it will beobserved that the telephone instrument 14 through which. messages arereceived and transmitted, is connected to telephone lineo4 which n turnis connected by line as to a conditioned line clearing circuit generallyreferred to by reference'numeral 68 which electrically interconnects thecomponents of the relay device it The telephone return line 7% isconnectedto the lineclearing circuit 68 through the telephone hookswitch 72 so that the tele phone circuit may be completed when the handpiece of the. telephone is removed to close the telephone line switchdevice 72in a manner well known to those skilled I in the art. As willbe apparent from FIGURE 9, nor- 7 switch 72.

cess push button 18 although initially disposed in its ductor 75 isconnected to the other terminal of the switch box 56 for completing acircuit through the hook switch 72 when closed to the return telephoneline 70. Itwill also be observed that the capacitor 62 is connectedacross the terminals of the switch box 56. r

Assuming therefore that the hook switch ,72 is inadvertently closedbecause of accidental uncradling of the telephone handpiece, it willbe'apparent that the" tele'- is capable of ringing the telephoneinstrument 14 to call attention to the telephone subscriber if at home dalso to energize the relay coil 24' which is connected in the circuit byvirtue of the inadvertent closingofthe hook It will be" apparenttherefore, that the relatched position'compressing the spring element44, may upon release thereof, move upwardly to an unlatched position byvirtue of the fact that the hook switch 72 is in 7 closed position outof engagement with the push button 18. Energization of the relay coil 24will therefore draw the armature portion '28 or the relay operating arm'upwardly to pivot the relay operating arms in a clockwise direction wasviewed in FIGURE 9 to open the contacts of the switch members and 54'.The line clearing circuit 63 would therefore be immediately opened wereit not for the presence of the capacitor 62. The capacitor 62 willtherefore provide a temporary time interval during which a sufficientholdingcurrent will flowthrough the line clearing circuit to maintainthe operating arm in operative position as described with respect toFIGURE 5 so that the latch mechanism 42 may become unlatched to releasethe reset button Upon' cessation of the signal current, the operatingarms of the relay mechanism will remain in operative position by virtueof the action of the latching mechanism as hereinbefore describedAccordingly, the telephone circuit for the telephone instrument 14 willbe opened by'virtue of the open conditiori of the line clearing circuit68. The telephone line will then be availablev to the other subscribers.Restoration of normal telephone service to the telephoneinstn. ment 14may 'be accomplished by subsequently replacing the hand-piece so as toopen the line switch 72 and engage the push button 18 to restore thelatch mechanism 42, in which case the operating arms of the relaymechanism will return to their inoperative position and be relatchedtherein. once again close so that the telephone circuit will be restoredto normal operation and the line clearing circuit 68 will again beconditioned for reception of a line clearing signal when needed. 7 i

From the foregoing description operation and utility of the lineclearing device, and system will be apparent. It will therefore beappreciated, that the present line clearing system in addition'tobringing to the attention of the. subscriber the uncradled condition ofthe telephone will also unlike previous line clearing systems actuallydisconnect the uncradled telephone from the line so that othersubscribers may use their telephones. However, at any time desired, onemay restore normal operation of the telephone which has beendisconnected by the line 7 clearing signal by'rnerely'engagingv thereset button 18 to a restore the line clearing circuit to its originalclosed condition. Accordingly, anyaccidental disconnection of onetelephone by an erroneously dispatched line clearing signal duringconversation may be immediately rectified im- 7 der control of thesubscriber.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those The line clearing circuit 68 will then 33 skilledin the art, it is not desired to limit the invention to the exactconstruction and operation shown and described, and accordingly allsuitable modifications and equivalents may be resorted to, fallingwithin the scope of the invention as claimed.

What is claimed as new is as follows:

1. A telephone line clearing system comprising in combination with atelephone receiving circuit having a handpiece actuated hook switch,normally closed line clearing circuit means operatively responsivethrough the hook switch to close the telephone receiving circuit, meansinstantaneously responsive to a line clearing signal to open the lineclearing circuit means for the disconnecting of the telephone receivingcircuit and delayed restoration thereof to a closed condition, latchmeans releasable by said hook switch for holding the line clearingcircuit open prior to restoration to said closed condition andselectively actuated reset means rendered operative upon release of saidlatch means and following reception of said line clearing signal torestore the line clearing circuit means to a closed conditionindependently of the hook switch.

2. The combination of claim 1, wherein said signal responsive meansincludes relay means energized in response to a signal current irl theline clearing circuit means to open the line clearing circuit means anddelay m ans for maintaining said relay means energized for a delayperiod after cessation of said signal current to permit operation ofsaid latch means.

3. The combination of claim 2, wherein said reset means includesselective actuator means operatively connected to a latch means fordisplacement thereof to a position restoring the line clearing circuitmeans to a closed condition after cessation of the signal and means forholding the latch means in said line restoring position independently ofthe hook switch.

4. The combination of claim 1, wherein said reset means includesselective actuator means operatively connected to the latch means fordisplacement thereof to a position restoring the line clearing circuitmeans to a closed condition after cessation of the signal and means forholding the latch means in said line restoring position independently ofthe hook switch.

5. The combination of claim 4 including time delay means in the lineclearing circuit means to temporarily maintain the line clearing circuitmeans closed after reception of the line clearing signal so as to permitoperation of the latch means.

6. The combination of claim 1, including time delay means in the lineclearing circuit means to temporarily maintain the line clearing circuitmeans closed after reception of the line clearing signal so as to permitoperation of the latch means.

7. In a telephone set having a switch hook and a message circuit, anauxiliary switching means comprising; a

fixed support spaced from the switch hook, normally closed contacts onthe support, signal responsive means movably mounted by th support toinstantaneously open the contacts when displaced to a circuit openingposition by a line clearing signal, latching means movably mounted onthe support for displacement to a release position for holding thesignal responsive means in said circuit opening position after receptionof said line clearing signal, means on the signal responsive meanspreventing displacement or" the latch means to said release positionwhen the switch hook is closed in the absence or" a line clearingsignal, and means on the latch means engageable by the switch hook whenopen for disabling the latch means.

8. In a telephone set having a switch operating mechanism controlled byremoval and replacement of the handset on its cradle and a receivingcircuit, a normally closed auxiliary switch mounted on a defiectablearm, auxiliary switch opening means engageable with the auxiliary switchto deflect said arm, latch means for retaining the switch opening meansin a position holding the auxiliary switch open only when the handset isremoved from its cradle, auxiliary signal responsive means operativelycormected to the switch open'mg means for movement thereof to saidposition in response to a line clearing signal when the handset isremoved from its cradle and for delayed return of said switch openingmeans to an initial position such that the arm is returned to anundeflected position and means for disabling the latch means when thehandset is replaced on its cradle.

9. In a line clearing system for use with a telephone subset havmg ahook switch closed upon removal of a handset from a cradle unit to closea message circuit, an auxil ary control unit comprising, support meansfixedly mounted in the cradle unit in spaced relation to the hookswitch, line clearing circuit means operatively connected to saidmessage circuit for receiving a line clearing signal in a closedcondition, means responsive to said sig nal for instantaneously openingsaid line clearing circuit means and restoring the line clearing circuitmeans to said closed condition after a delay period following cessationof the signal, latch means mounted by the support means in releasableengagement with the hook switch for movement to a circuit openingposition during said delay period for holding the line clearing circuitmeans in an open condition, and reset means connected to the latch meansfor restoring the line clearing circuit means to said closed conditionindependently of the hook switch for selectively rendering the messagecircuit operative.

References Cited in the file of this patent UNITED STATES PATENTS

1. A TELEPHONE LINE CLEARING SYSTEM COMPRISING IN COMBINATION WITH ATELEPHONE RECEIVING CIRCUIT HAVING A HANDPIECE ACTUATED HOOK SWITCH,NORMALLY CLOSED LINE CLEARING CIRCUIT MEANS OPERATIVELY RESPONSIVETHROUGH THE HOOK SWITCH TO CLOSE THE TELEPHONE RECEIVING CIRCUIT, MEANSINSTANTANEOUSLY RESPONSIVE TO A LINE CLEARING SIGNAL TO OPEN THE LINECLEARING CIRCUIT MEANS FOR THE DISCONNECTING OF THE TELEPHONE RECEIVINGCIRCUIT AND DELAYED RESTORATION THEREOF TO A CLOSED CONDITION, LATCHMEANS RELEASABLE BY SAID HOOK SWITCH FOR HOLDING THE LINE CLEARINGCIRCUIT OPEN PRIOR TO RESTORATION TO SAID CLOSED CONDITION ANDSELECTIVELY ACTUATED RESET MEANS RENDERED OPERATIVE UPON RELEASE OF SAIDLATCH MEANS AND FOLLOWING RECEPTION OF SAID LINE CLEARING SIGNAL TORESTORE THE LINE CLEARING CIRCUIT MEANS TO A CLOSED CONDITIONINDEPENDENTLY OF THE HOOK SWITCH.